Portion of a boot upper



FIG. 1 is a left side elevational view of a first embodiment of a portion of a boot upper, showing my new design;

FIG. 2 is a front, left side perspective view thereof;

FIG. 3 is a left side elevational view of a second embodiment of a portion of a boot upper, showing my new design; and,

FIG. 4 is a front, left side perspective view thereof.

The broken lines shown on the bow are intended to disclaim the interior portions of the bow. The broken lines illustrating the boot are only for context and form no part of the claimed design. 

CLAIM The ornamental design for a portion of a boot upper, as shown and described. 